Played a game with this where I was drawing my deck with a few artificers left over and a crypt in hand. Realized I could discard nothing to topdeck coppers and draw them, boosting triumph points and then setting the coppers aside with crypt.

Don't know if someone has put this one up yet, and it might even be useful enough to be considered a combo, because you can build your strategy around this (or at least, I did).Lurker + Prince

Lurkers make gaining Prince really easy, so that they don't compete with Province anymore. They also really like being Princed. The more Princed Lurkers you have, the easier gaining Princes becomes, and you keep getting free Action card gains to build a quick engine (without need of villages) until you're ready for an easy 3-pile.

Side note: the presence of Watchtower is great for this interaction because of the topdecking effect. The Princes can become useful the very next turn, and you can make sure they collide with your Lurkers by gaining them at the right time.

Transmogrify + Cemetery was fun. Transmogrify sucks at trashing cost junk, but Transmogrifying a Silver into a Cemetery lets you trash all the other junk in your hand. And if you have another Transmogrify on the mat, you can instantly turn that Cemetery into a useful !

Forager + Treasurer was really nice too. Trash that Gold for the Forager bonus, then get it right back in hand for your payload. I just played a game that had Salvager too and it all worked very nicely together.